Zeolite application contributes to remediation of lead-polluted soil by spinach

Abstract

Remediation of lead (Pb)-contaminated soils is increasingly important because production of food crops in these soils is associated with human health risk. The present study investigated use of natural zeolite to remediate Pb-contaminated soil by quantifying changes in soil properties, soil nutrients and distribution of Pb in spinach plant parts. Natural zeolite was added to pots containing four different soil media that were artificially amended with Pb in a greenhouse. Zeolite was mixed with the media at four rates plus a zero control, and for three of the Zeolite rates a second application was made to the soil surface in the pot 30 days later for a total of eight zeolite treatments. The 32 treatments were replicated four times. Pb immobilization by zeolite was dose dependent, with greater immobilization at higher zeolite rates. Heterogeneous soil humus components exerted both mobilizing and stabilizing effects, so the medium nutrition was most effective for phytostabilization. So,split applications of zeolite were more effective than once, because the lag-phase time of split zeolite treatment applications was longer than for one application, to the same total dosage. This method might be an efficient way to remediate the lead-polluted soils with zeolite application twice.